Skip to main content

Snail's Venom Puts Fish in Insulin Coma

The cone snail's venom contains not only neurotoxins, but insulin, too—which stuns the fish it preys on. Christopher Intagliata reports

Science Quickly

On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


It may not be the legendary matchup squid vs octopus, but imagine this fight: sea-dwelling cone snail versus tiny fish! Who wins? Well, true, the fish can dart away. But the snail has chemical weapons. "So they use a whole cocktail of compounds and most of them are neurotoxins and they just completely wipe out the prey's physiology, right, so they prey cannot respond anymore."

Helena Safavi, a biologist at the University of Utah. She and her colleagues discovered that the cone snail's venom contains not only neurotoxins, but insulin, too—which the snail's prey take in through their gills. And that insulin overdose causes the fish's blood sugar to plummet, depriving its brain of energy, and inducing a coma.

"And that's what happens when you give people an insulin overdose—you can cause coma and then death depending on the amount of insulin." They report the findings in the journal Proceedings of the National Academy of Sciences. [Helena Safavi-Hemami et al, Specialized insulin is used for chemical warfare by fish-hunting cone snails]

If this all sounds like something out of a murder mystery… well, it is. The paper actually cites the Claus von Bülow trials in the 1980s. [American Justice clip: "Claus von Bülow injected his wife with insulin. And as a consequence of that, she went into insulin shock. And ended up in an irreversible coma. That was the prosecution theory. But proving it to a jury would be a struggle…"] Von Bülow was ultimately found not guilty. But in this evolutionary struggle between snail and fish…it's now clear who done it. And how. 

—Christopher Intagliata

[The above text is a transcript of this podcast.]
 

Snail's Venom Puts Fish in Insulin Coma